Method and apparatus for feeding single sheets



June 3, 1969 w. F. BISHOP 3,447,799

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3,447,799 METHOD AND APPARATUS FOR FEEDING SINGLE SHEETS Filed May 5, 1967 W. F. BISHOP June 3, 1969 June 3, 1969 w. F. BISHOP 3,447,799 METHOD AND APPARATUS FOR FEEDING SINGLE SHEETS Filed May :5, 1967 Sheet 3 of 3 I 771151: Walter @2871 0p- 7 By 96%) war?! United States Patent 3,447,799 METHOD AND APPARATUS FOR FEEDING SINGLE SHEETS Walter F. Bishop, Elk Grove Village, Ill., assignor to Bell & Howell Company, Chicago, 11]., a corporation of Illinois Filed May 3, 1967, Ser. No. 635,889 Int. Cl. B65h 3/06 US. Cl. 271-21 12 Claims ABSTRACT OF THE DISCLOSURE Feeding of single sheets from a stack of sheets, employing a spaced pair of fixed sheet separators, one at each side of the stack, each sheet separator having a comb-like configuration with a number of teeth blocking the front of the stack of sheets. Individual sheets are fed through restricted passageways between the teeth.

The present invention relates to a device for insuring that only one sheet is fed at one time from a stack of sheets. Such devices have important applications for use with duplicating and other reproducing apparatus into which individual sheets of paper must be fed.

Sheet feeding is conventionally accomplished by a driving member frictionally engaging the topmost sheet of the stack of sheets and forcing the sheet forward past an obstruction. The obstruction, or sheet separator, is provided to block the forward edge of the stack of sheets so that only the topmost sheet is moved. Various types of sheet separators have been previously developed. However, prior sheet separators have generally been of the pin type, which must be vertically movable, or have required special sheet driving arrangements, or have had other disadvantages. The present invention provides effective sheet separation by employing sheet separators which are of simple and rugged construction and very low cost, yet provide effective feeding of only individual sheets. The sheet separators may be fixed integral units and do not require any moving parts. A plurality of teeth project inwardly to define a plurality of sheet stops blocking the edges of the stack of sheets. The teeth are spaced apart to define a plurality of restricted sheet feeding passageways for individual sheets therebetween, and may be vertically staggered to block only one side of the sheet. Feeding is accomplished by blocking the forward movement of the stack of sheets at the sides of the forward edge of the stack in plural vertically spaced areas of the stack and forcing the top sheet forward.

Further objects, features and advantages of the invention pertain to the particular arrangement and structure whereby the above-mentioned aspects of the invention are attained. The invention will be better understood by reference to the following description and to the drawings forming a part thereof, which are substantially to scale, wherein:

FIGURE 1 is a front elevational embodiment of the invention;

FIGURE 2 is a top plan view of the embodiment of FIGURE 1;

FIGURE 3 is a side view of the embodiment of FIG- URES 1 and 2;

FIGURE 4 is a front elevational view of the sheet separator in FIGURES 1 through 3;

FIGURE 5 is a side view of the sheet separator of FIGURE 4;

FIGURE 6 is a front elevational view of an alternate sheet separator in accordance with the invention;

FIGURE 7 is a side view of the sheet separator of FIGURE 6;

view of an exemplary 3,447,799 Patented June 3, 1969 FIGURE 8 is a rear elevational view of a further sheet separator in accordance with the invention;

FIGURE 9 is a rear elevational view of a further sheet separator in accordance with the invention;

FIGURE 10 is a side view of the sheet separator of FIGURE 9;

FIGURE 11 is a rear elevational view of another sheet separator in accordance with the invention;

FIGURE 12 is a side view of the sheet separator of FIGURE 11;

FIGURE 13 is a rear elevational view of a further sheet separator in accordance with the invention;

FIGURE 14 is a side view of a sheet separator of FIGURE 13;

FIGURE 15 is a rear elevational view of a further alternative sheet separator in accordance with the invention; and

FIGURE 16 is a side view of the sheet separator of FIGURE 15.

Referring first to FIGURES 1 through 3, there is shown a sheet feeding apparatus 30 in accordance with the present invention. The sheet feeding apparatus 30 includes a pair of sheet side guides 32 laterally containing a stack of paper sheets 34 therebetween. Partially obstructing the forward end of the stack 34 is a spaced pair of exemplary sheet separators 36 in accordance with the invention. Each sheet separator has a plurality of teeth spaced apart to define sheet stops and sheet feeding passageways therebetween. These passageways provide restricted feeding of individual sheets therethrough.

Preferably, the sheets are fed through the pair of sheet separators 36 by a frictional sheet drive 38. The sheet drive 38 here comprises a conventional rotary powered drive shaft 40 upon which is axially fixed a pair of cylindrical frictional drive wheels 42. Such sheet drives are known in the art and accordingly need not be described in detail herein. The shaft 40 is biased downwardly so that the drive wheels 42 continuously frictionally engage the surface of the uppermost sheet 44 of the stack 34 as the stack is lowered by progressive feeding of sheets. Preferably, the shaft 40 is at a fixed spaced distance from the pair of sheet separators 36.

The side guides 32a and 32b may be of generally con ventional construction and accordingly need not be described herein in detail. They are preferably positioned to provide parallel spaced vertical surfaces 46a and 46b parallel the direction of feeding of the paper so as to contain the stack 34 laterally, but provide an open forward edge for paper feeding. Preferably the side guides are mounted on a platen 48 in such a manner as to be laterally adjustable to accommodate varying Widths of paper by changing the distance between the surfaces 46a and 46b.

The respective left and right sheet separators 36a and 36b are preferably mounted in a vertical plane at the forward edge of the respective side guides 32a and 32b and perpendicular thereto. They are preferably rigidly fixed to the side guides by bolts, rivets, welding, adhesive or other suitable conventional fastening arrangements. The teeth of each sheet separator preferably extend A; to A inch toward one another into the paper containing area between the side guides to define a plurality of sheet stops blocking the outside edges of the stack of sheets 34. The separators are positioned so that the roots of the teeth are generally aligned with the vertical surfaces 46a or 46b of the side guides. Vertically elongated mounting slots 49 in each sheet separator provide for slight adjustments in the mounting position of each sheet separator on its side guide.

Referring now to the specific sheet separators 36a and 36b, shown in detail in FIGURES 1, 4 and 5, it will be appreciated that various of the features are common to the other embodiments of sheet separators disclosed herein. Accordingly, the description of the sheet separators 36a and 36b is intended to be equally applicable to said embodiments where appropriate. It may be seen that the sheet separators are fixed integral units without any moving components.

The vertical extent of the sheet separators 36a and 36b are approximately equal to that of the side guides and preferably at least equal to or greater than the maximum height of the stack of paper to be fed. The sheet separators 36a and 361; are preferably substantially an allochiral or mirror image pair of unitary comb-shaped thin planar members which contain here three teeth or fingers 50. Each separator performs the same function at opposite sides of the front edge of the stack of sheets 34. It

will be appreciated that the number of fingers will vary with the desired height of the separator since preferably the entire vertical extent of the inside edge of the separator is toothed. The teeth 50 have sheet feeding passageways 52 between each tooth. Each passageway 52 provides an unobstructed opening from the paper feeding area through the sheet separator. All of the passageways 52 are preferably of equal dimensions and equally spaced apart. The passageways 52 are even and are defined by the opposing surfaces of the adjacent teeth 50. The stack of sheets is retained and selectively blocked by the inside faces 53 of the teeth 50.

All of the sheets in the stack are abutted by at least one tooth 50 at at least one side of the stack even though the teeth are spaced apart. The outer edges of each sheet preferably deflect upwardly to pass through a passageway 52. This deflection or buckling of the sheet edge assists in sheet separation. Preferably the lateral dimensions between the innermost ends of the vertically corresponding passageways 52 on the opposing sheet separators 36a and 3617 provide a distance slightly greater than the Width of the sheet to be fed. However, it will be appreciated that this distance need not be linear since the edge of the top sheet may tilt upwardly to pass through the passageways 52, as shown in FIGURE 1.

In the operation of the sheet feeding apparatus the teeth provide a slight obstruction to the forward movement of any of the sheets in the stack 34. The sheet drive 38 engages and forces forward the uppermost or top sheet 44. As the forward edge of the top sheet 44 is forced against the tooth 50 immediately in front of it, it is vertically deflected and forced upwardly over the inside face 53 of that tooth 50 until it is free to pass through the passageway 52 immediately above that tooth.

Preferably the outermost edge of the top sheet 44 is deflected upwardly to a greater extent than the rest of the top sheet, and the top sheet 44 is accordingly buckled laterally as Well as vertically. Due to the obstruction provided .by the tooth, and any distortion or buckling of the sheet, the top sheet 44 is readily separated from the immediately underlying sheet.

Because of the very limited vertical extent of the obstruction provided by any individual tooth 50, the top sheet 44 does not have to buckle or distort, or be force fed, to any substantial extent. The top sheet needs to flick over only the single tooth 50 which is immediately in front of it and is guided restrictively through the passageway 52 immediately above that one tooth. Consedanger of a sheet folding over or otherwise misfeeding. Also, it may be seen that only the outer edges of the sheet must distort during feeding, as there is no obstruction of any of the sheets except at their outside edges.

It may be seen that the left sheet separator 36a is vertically staggered with respect to the right sheet separator 36b. That is, although the left and right sheet separators are basically identical, each tooth 50 on one sheet separator is opposite, and may correspond in position and shape to, the sheet feeding passageway 52 on the opposite sheet separator. For any given top sheet being fed only one quently, there is no 4 side of the sheet is obstructed by a tooth 50, yet taking both sides together the teeth block the entire stack of sheets, and here provide six vertically spaced teeth.

On the sheet separator pair 36 the teeth 50 are regular, and evenly vertically staggered with respect to the opposing teeth on the facing sheet separator. The shape of each tooth 50 is a large regular inwardly tapering trapezoid, with both the top and bottom surfaces vertically sloped. The apexes of all the teeth 50 are vertically truncated on the same line and thus project the same distance horizontally.

Turning now to the embodiment of the invention illustrated in FIGURES 6 and 7, it may be seen that a sheet separator pair 56 illustrated therein is basically similar to the sheet separator pair 36. In this sheet separator pair the teeth are also vertically staggered with respect to one another, but the tooth configuration is triangular or sawtooth rather than rectangular. That is, the bottom. edge of each tooth is a generally horizontal surface and the top edge of each tooth is downwardly pitched and converges with the bottom edge'at a rounded apex. There are 5 teeth on each separator.

FIGURE 8 illustrates a sheet separator pair 57; In this embodiment the entire comb or tooth portion is preferably formed by a bent round wire 58 formed into multiple parallel loops or bights 59. The loops 59 are evenly vertically spaced apart to define narrow restricted sheet feeding passageways 60 therebetween. The wire 58 may be Welded or otherwise suitably mounted to a separate plate or bracket 61 for fastening to the side guides if desired.

FIGURES 9 and 10 illustrate a further pair of sheet separators 62. It differs in that the comb structure thereon is defined by a plurality of closely vertically spaced apart spherical balls 64. Each ball 64 is mounted for independent rotation centrally about a horizontal axis and rotates as the top sheet is fed between a given pair of balls.

FIGURES l1 and 12 illustrate a sheet separator pair 66. This sheet separator pair ditfers in that the teeth 68 thereon are substantially larger than the sheet feeding passageways 70 therebetween. It may be seen that the passageways 70 are generally horizontal but taper inwardly, i.e. the vertical height of the passageway is reduced as the passageway extends inwardly of the sheet separator. The teeth 68 may be constructed separately and then assembled and bonded together by a backing plate 69 or other suitable means.

FIGURES 13 and 14 illustrate a sheet separator pair 72 differing from the above described sheet separator pairs in that the teeth 74 are elongated regular rectangles and extend horizontally. 9 teeth are provided per sheet separator.

FIGURES 15 and 16, for example, illustrate another type of sheet separator pair 78. The teeth of the sheet separator pair 78 are vertically staggered with respect to one another, but diifer in that each tooth 80 thereon is relatively large in vertical extent and has a tang 82 projecting from its interior or paper abutting surface. The tang 82 is at the lower edge of each tooth and provides an upward sloping ramp surface for assisting in deflecting sheets upwardly over the tooth 80. v

The construction of any of the above described sheet separators is extremely simple and economical. They may be stamped, cast or machined from sheet metal, plastic or any other suitable materials. It will be appreciated that various of the configurations and features taught herein may be combined to form other sheet separators.

It may be seen that there has been described herein improved apparatus for feeding individual sheets from a stack of sheets, which apparatus is extremely simple, reliable and effective and may be manufactured at low cost in various forms. The apparatus described herein is presently considered to be preferred; however, it is contemplated that further variations and modifications within the purview of those skilled in the art can be made herein. The following claims are intended to cover all such variations and modifications as fall Within the true spirit and scope of the invention.

The embodiments of the invention in which an exclusive property or privilege is claimed as defined as follows:

1. Apparatus for feeding individual sheets from a stack of sheets, said apparatus having a spaced pair of side guides adapted to contain a stack of sheets therebetween, wherein the improvement comprises:

a pair of fixed sheet separators,

each said sheet separator having a comb configuration with a plurality of teeth projecting inwardly between said side guides to define a plurality of sheet stops for blocking the feeding of sheets,

said teeth being spaced apart to define a plurality of sheet feeding passageways therebetween,

said sheet feeding passageways being adapted to provide restricted sheet feeding therethrough.

2. The apparatus of claim 1 further including rotary frictional drive means at a preset fixed distance from said sheet separators for engaging and moving the uppermost sheet of a stack of sheets through said sheet separators.

3. The apparatus of claim 1 wherein said teeth provide the sole obstruction to the feeding of sheets from a stack of sheets.

4. The apparatus of claim 1 wherein said teeth are substantially identical, vertically aligned and evenly spaced.

5. The apparatus of claim 1 wherein said teeth on one said sheet separator are vertically staggered with respect to said teeth on the other said sheet separator to block only one side of any individual sheet of a stack of sheets.

6. The apparatus of claim 1 wherein said pair of side guides are an allochiral pair.

7. The apparatus of claim 1 wherein each said sheet separator is rigidly fixed to one of said side guides.

8. The apparatus of claim 1 wherein said sheet feeding passageways terminate adjacent said side guides.

9. Apparatus for feeding individual sheets from a stack of sheets, said apparatus having means for supporting a stack of sheets, and sheet driving means for moving the top sheet of said stack of sheets forward, wherein the improvement comprises:

a pair of fixed abutment means spaced at each side of the stack of sheets,

said abutment means having plural projections extending substantially horizontally in front of said stack of sheets,

said projections being vertically spaced apart to define sheet feeding spaces therebetween,

each individual projection being positioned to obstruct the forward movement of only a portion of the sheets in the stack of sheets, and being positioned to deform and deflect an adjacent moving top sheet into a sheet feeding space.

10. Apparatus for feeding individual sheets from a stack of sheets, said apparatus having a spaced pair of side guides adapted to contain a stack of sheets therebetween and having frictional sheet drive means for engaging and moving the uppermost sheet of a stack of sheets, wherein the improvement comprises:

a sheet separator fixed to each of said side guides,

each said sheet separator having a comb configuration with a multiplicity of teeth projecting substantially horizontally and inwardly between said side guides to define a multiplicity of sheet stops providing the sole obstruction to the feeding of sheets from the stack of sheets,

each said tooth providing an obstruction to the forward movement of a portion of sheets of the stack of sheets,

said multiplicity of teeth having a vertical extent of at least the maximum height of the stack of sheets,

said teeth being vertically spaced apart to define a plurality of sheet feeding passageways therebetween, said sheet feeding passageways being adapted to provide restricted sheet feeding therethrough. 11. A method for feeding single sheets from a stack of sheets comprising the steps of:

blocking the forward movement of a stack of sheets at the sides of the forward edge of the stack in plural vertically spaced areas and leaving plural vertically spaced areas of said stack unblocked therebetween,

and engaging the uppermost sheet of said stack of sheets and forcing it forward.

12. The method of claim 11 wherein the opposite sides of the stack are blocked in vertically different but equally vertically spaced areas.

References Cited UNITED STATES PATENTS 3,239,212 3/1966 Springer 27119 RICHARD E. REGERTER, Primary Examiner, 

